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• Converting from MXF to MPEG format with FFmpeg [migrated]

  2 mars 2013, par user2060812

  We're trying to convert .mxf video to .mpeg on ffmpeg-0.9.2 and looks like 0.9.2 version doesn't support .mxf conversion to .mpeg.

  We don't want to switch on latest 0.11 version of ffmpeg as the video result is too poor for latest version. Maybe we're not using the right command to convert .mxf format.

  Below is the error on conversion command :

  [root@localhost ~]# ffmpeg -i test.mxf  -ac 2 output.mpg                                                                                     ffmpeg version 0.9.2-syslint, Copyright (c) 2000-2012 the FFmpeg developers
  
    built on Mar  1 2013 22:34:33 with gcc 4.6.3
  
    configuration: --prefix=/usr/local/cpffmpeg --enable-shared --enable-nonfree --enable-gpl --enable-pthreads --enable-libopencore-amrnb --enable-decoder=liba52 --enable-libopencore-amrwb --enable-libfaac --enable-libmp3lame --enable-libtheora --enable-libvorbis --enable-libx264 --enable-libxvid --extra-cflags=-I/usr/local/cpffmpeg/include/ --extra-ldflags=-L/usr/local/cpffmpeg/lib --enable-version3 --extra-version=syslint
  
    libavutil    51. 32. 0 / 51. 54.100
  
    libavcodec   53. 42. 4 / 53. 42. 4
  
    libavformat  53. 24. 2 / 53. 24. 2
  
    libavdevice  53.  4. 0 / 53.  4. 0
  
    libavfilter   2. 53. 0 /  2. 77.100
  
    libswscale    2.  1. 0 /  2.  1.100
  
    libpostproc  51.  2. 0 / 51.  2. 0
  
  Input #0, mxf, from `test.mxf`:
  
    Duration: 00:00:07.04, start: 0.000000, bitrate: 62580 kb/s
  
      Stream #0:0: Video: mpeg2video (4:2:2), yuv422p, 720x608 [SAR 608:405 DAR 16:9], 50000 kb/s, 25 fps, 25 tbr, 25 tbn, 50 tbc
  
      Stream #0:1: Audio: pcm_s16le, 48000 Hz, 8 channels, s16, 6144 kb/s
  
  File `output.mpg` already exists. Overwrite ? [y/N] y
  
  Incompatible pixel format `yuv422p` for codec `mpeg1video`, auto-selecting format `yuv420p`
  
  [buffer @ 0x8476e0] w:720 h:608 pixfmt:yuv422p tb:1/1000000 sar:608/405 sws_param:
  
  [buffersink @ 0x847b80] auto-inserting filter `auto-inserted scaler 0` between the filter `src` and the filter `out`
  
  [scale @ 0x848220] w:720 h:608 fmt:yuv422p sar:608/405 -> w:720 h:608 fmt:yuv420p sar:608/405 flags:0x4
  
  [mpeg @ 0x84a7a0] VBV buffer size not set, muxing may fail
  
  Output #0, mpeg, to `output.mpg`:
  
    Metadata:
  
      encoder         : Lavf53.24.2
  
      Stream #0:0: Video: mpeg1video, yuv420p, 720x608 [SAR 608:405 DAR 16:9], q=2-31, 200 kb/s, 90k tbn, 25 tbc
  
      Stream #0:1: Audio: mp2, 48000 Hz, 2 channels, s16, 128 kb/s
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (mpeg2video -> mpeg1video)
  
    Stream #0:1 -> #0:1 (pcm_s16le -> mp2)
  
  Press [q] to stop, [?] for help
  
  [buffer @ 0x8476e0] Changing frame properties on the fly is not supported.
  
  Failed to inject frame into filter network

• Programatically get non-overlapping images from MP4

  15 février 2013, par Carlos F

  My ultimate goal is to get meaningful snapshots from MP4 videos that are either 30 min or 1 hour long. "Meaningful" is a bit ambitious, so I have simplified my requirements.

  The image should be crisp - non-overlapping, and ideally not blurry. Initially, I thought getting a keyframe would work, but I had no idea that keyframes could have overlapping images embedded in them like this :

  Of course, some keyframe images look like this and those are much better :

  

  I was wondering if someone might have source code to :

  Take a sequence of say 10-15 continuous keyframes (jpg or png) and identify the best keyframe from all of them.

  This must happen entirely programaticaly. I found this paper : http://research.microsoft.com/pubs/68802/blur_determination_compressed.pdf

  and felt that I could "rank" a few images based on the above paper, but then I was dissuaded by this link : Extracting DCT coefficients from encoded images and video given that my source video is an MP4. Of course, this confuses me because the input into the system is just a sequence of jpg images.

  Another link that is interesting is :

  Detection of Blur in Images/Video sequences

  However, I am not sure if this will work for "overlapping" images.

  Any ideas ?

• How to convert audio stream from PureTool/CVS video ?

  1er janvier 2013, par Mark

  I apologize if there is a better place to post this. I recently came across a couple CVS single-use video cameras that I had been using back in 2005. I still have the USB cable I made and now that I've switched to Mac I can use Puretool to extract the old videos from the cameras. The problem I'm having is that I can only hear the audio when viewing the videos with VLC media player. I read on PureTools site, a common problem is that the audio codec used is incompatible with Quicktime and the audio stream needs to be converted. There is a link on their site to a program called FixSound which is purported to fix this, but the link is dead and I've been unable to find any further information about this. If anyone could point me in the right direction, I'd be very grateful. All the videos I'm dealing with are from the first year of my son's life and I'd really like to be able to archive them in a more uniform format. I would think this would be possible to do using Adobe Audition or some other program in Adobe's CS6 Master Collection but I've only dealt with Photoshop, Illustrator, Dreamweaver, Flash & Fireworks. I have no experience with audio or video yet.

  Thanks,

  Mark